Unless otherwise configured, the client libraries use Application Default Credentials to authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing the UnifiedCredentialsOption The following example shows how to explicitly load a service account key file:
[](std::string const& keyfile) {
auto is = std::ifstream(keyfile);
is.exceptions(std::ios::badbit); // Minimal error handling in examples
auto contents = std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
auto options =
google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
google::cloud::MakeServiceAccountCredentials(contents));
return google::cloud::servicecontrol_v1::QuotaControllerClient(
google::cloud::servicecontrol_v1::MakeQuotaControllerConnection(
options));
}
Follow these links to find examples for other *Client classes:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-03-14 UTC."],[[["This document provides a guide on how to override default authentication credentials when using Google Cloud Client Libraries, using a service account key file as an example."],["The latest available version is 2.37.0-rc, and this document includes a list of version-specific links dating back to version 2.11.0 for reference on overriding authentication."],["The client libraries typically use Application Default Credentials (ADC) for authentication, but `UnifiedCredentialsOption` allows for overriding this default."],["Examples are available for `QuotaControllerClient`, and `ServiceControllerClient` classes."],["It's important to consult the \"Best practices for managing service account keys\" guide for detailed service account management advice, along with the \"Authentication Components\" for more information about creating credentials."]]],[]]
